Matic electric inc



Aug. 13, 1929. JJRAY AUTOMATIC TELEPHONE SYSTEM Original Filed July" 1925 Patented Aug. 113, 1929.

Sl AliTllS warren rather OFFICE.

ARTHUR, 3. any, or CUBA, ILLINOIS, ASSIGNOR, nYi/insnn vessnnnvinnrs, TO AUTO- MATIC ntnc'rnro inc, on CHICAGO, ILLINDIS, a CORPORATION OF DELAWARE.

AUTOIHATIG TELEPHONE SYSTEM.

Application filed. July 6, 1925, Serial No. 41,485.

This invention relates to auton'iatic telephone systems in general, but is more particularly concerned with methods of establishing toll or long distance connections and local connections to subscribers in an automatic party-line telephone system; and the object, broadly stated, is the provision. of a new and improved combination toll and lo-' 'al automatic party-line connector.

In a local auton'iatic telephone system containing party-lines, an ordinary local call is extended from one local subscriber to another local subscril'ier through the medi um of tllilOHlAtlC switches responsive to impulses dialled by means of a calling deviccby the.

local calling subscriber. The automatic switches employed in setting up this connec tion may consist, tor example, of a line switch, one or more selector switches, de pending on the size of the local system, and a connector switch. he function of the line switch is to extend the connection to an idle first selector. The selectors are each responsive to a digit dialled by the calling subscriber and function. to extend the connection, to the succeeding switch and may be of any well known type, the vertical and rotary type, for example. Responsive to the last three digits dialled by the calling subscriber, two of which for line selection and a third for ringing current selection, the connector switch, which may also be of the vertical and rotary type with the addition of fretpichcy selecting mechanism, selects the called line, tests the called line, transmits the busy signal back to the calling subscriber if the called line is busy or applies the selected signalling current to, the called line iminediately upon finding the called line idle, and. finally completes the talking connection when the called. subscriber answers.

In such an automatictelcphone system an incoming toll call may also be extended to a local subscriber by a local toll operator at the local automatic exchange through the medium o'ta cord and jack and similar automatic switches, responsive to impulses dialed by the toll operator. The automatic switches employed in setting up a toll connection may again consist of one or more selector switches, each responsive to a digit dialed by the toll operator, and a connector Renewed. November 19, 1928.

switch. Responsive to the last three digits dialled by the tollioperator the connector,

which may be of a similar type referred to above, selects the called line, tests the called line, transmits the busy tone to the toll operator and ,alsocauses a visualindication of the busy condition, if the called line is busy, or seizes the called line if it is idle and gives visual indication thereof to the operator. The operator may then cause the connector to apply the selected signaling current, selected by a digit dialled previously, to the called line at her will, and when thecalled subscriber answers the connector will finally complete the talking connection. I l I it has been common practice in. telephone exchange systenis to provide special groups ot selectors accessible exclusively to the toll operator for extending toll connections." The reasons for. this are well known to those skilledin the art. Thetoll connectors also may be of a special type, used exclusively for toll connections. However, the connectors used. in completing toll connections and those used in completing local connections lend,

themselves very easily to combinations when such connectors do not serve party lines, that is, when they are not equipped with the he quency selecting mechanism. Thus, in any particular exchange, by providing several combination toll andlocal connectors that may be. used to complete either type of call, making the total number of connectors only a small number more than is required for the local connections, the special toll connectors can be dispensed with entirely, and a great saving in the total number of switches necessary can be realized. Heretofore, however, it has not been thought feasible to provide combination toll and local connectors equipped with the frequency selecting mechanism because of certain construction and circuit difficulties involved.

By the present invention these difficulties have been overcome and the object of providing a combination toll and local party line connector has been accomplished, as will be described in the following specification, reference being had to the accompanying drawing. 7

Referring now to the accompanying drawing, the new and improved combination toll and local party line connector is indicated by the reference character C. This connector is accessible at the banks of the toll transmission selectors, one set of bank contacts 7 57S, inclusive, being shown, and is also accessible at the banks of local selectors, one set of bank contacts 8587, inclusive, being shown.

Individual to the connector C is the frequency selecting mechanism indicated by reference character FS. Responsive to the last digit dialled, the frequency selecting mechanism operates to select a certain one of five generators to supply ringing current of a certain frequency. Only the one ringing generator R is shown. The busy machine B supplies the current for giving a busy tone when a called line is busy.

The party line comprising conductors 201 and 202 is one of the party lines terminating in the banks of the group of connectors containing connector 0. Individual to the party line is the line switch LS. This line switch is of the rotary type whose wipers have no normal position and move in a forward direction only. The individual substations of the party line are indicated by the reference characters A to A inclusive, the bells only of the substations A to A being shown.

For a description of the apparatus at the toll operators switchboard, and the transmission selector, reference may be made to U. S. Patent No. 1,633,149, issued June 21 1927.

Having explained the object of this invention and the apparatus involved, the operation of the equipment may now be explained more in detail. For this purpose it will now be assumed that a subscriber at the local automatic exchange desires connection with the party line substation A It will also be assumed that the exchange is a 10,000 line system. It will therefore require four digits to select a line, and an additional digit to select the frequency of ringing current when calling .a'substation on a party line. To initiate the call, the calling subscriber removes his receiver and dials the directory number of the substation A. Removing the receiver at the calling substation operates the line switch individual to that substation to select and connect the calling line to an idle first selector switch.

In response to the first digit dial-led, the first selector raises its wipers opposite the level of bank contacts at which access is had to the proper group of second selectors and rotates them to select a trunk to an idle second selector of that group. In response to the second-digit dialled, the second selector raises its wipers opposite the level of bank contacts having access to the proper group of connectors in whose banks the line to the substation A terminates, and then rotates its wipers to select a trunk to an idle one of these connectors. It will be assumed that the trunk selected is the trunk to connector C, comprising conductors 81, 82, 83, accessibleat the bank contacts, 85, 86, 87.

Upon the seizure of the connector C, a bridge, including the two line conductors of the calling substation and the talking conductors of the preceding switches is placed across the conductors 81 and 82, thereby closing a circuit for the line relay 3 of connector C by way of bank contacts 85 and 87, normally closed springs controlled by armat-ures 20 and 21, through the upper and lower windings of line relay 3 to battery and ground. Line relay 3 energizes and closes a. circuit for release relay 5 at armature 2 1- and its working contact. Release relay 5 opcrates and closes the holding circuit at armature 28 and its working contact. Ground potential is thus supplied by way of grounded working contact and armature 26, working contact and armature 28, to its private bank contacts 76 and 86, thereby preventing any toll selector and any other local selector from connecting with the connector C at this time, and also supplying a holding ground for the operated switches preceding the connector C. In operating, release relay 5 also prepares the impulsing circuit for the vertical magnet 15 at armature 29 and its working contact.

In response to the third digit dialled, the circuit of the line relay 3 is opened a plurality of times. lVhen' relay 3 falls back the first time, a circuit for the first impulse is closed from ground by way of armature 21 and the resting contact, armature 29 and the working contact, off-normal springs 62 and 61, through the winding of the series relay 6, and through the windings of the vertical magnet 15 to battery. Series relay 6 operates and prepares a circuit for the remaining impulses at armature 32 and the working contact. Upon the first vertical step of the switch the off-normal springs are shifted so that the remaining impulses to the vertical magnet traverse a new circuit. This is the same as the one traced above, except that it includes off-normal springs 62 and 63, and armature 82 and the working contact. Ver: tical magnet 15 thus operates to raise the switch wipers 95, 96 and 97 step by step until they are opposite the level of bank contracts in which the line extending to the substation A terminates. The slow-to-release series relay 6 maintains its armature attracted through the vertical mo ven'ient or" the switch. At the termination of the vertical movement, the series relay 6 deenergizes and transfers the impulsing circuit to the rotary r 16 at armature 32 by way of the re contact.

In response to the fourth digit dialled, a series of interruptions is again produced in the circuit of the line relay 3. At each reting traction of the armature 24, an impulse of current is sent to the rotary magnet 16 over a circuit extending trom ground by way of armature 24; and the resting contact, arma ture 29 and the working contact, oftnorrnal springs 62 and 63, armature 82 and the resting contact, resting contact and armature 42, armature 51 and the resting contact, and through the winding of the rotary magnet 16 to the battery. The multiple relay 11 energizes in multiple with rotary magnet 16 over an obvious circuit and places a shunt around armature 12 at armature 45 and the working contact, prepares a testing circuit at armature 414 and the working contact, and at armature 46, opens a point in the initial energizing circuit of ringing control relay 18, to be described later. The rotary magnet 16 operates and rotates the switch wipers 95, 96, and 97 into engagement with the connector bank contacts associated with a line to substation A thesebeing bank contacts 185, 186, and 187. The multiple relay 11, being slow to release, maintains its armature attracted throughout the rotary movement.

If the line to substation A is busy at this particular time, there will be ground poten tial on the test contact 186, supplied to it either by another connector whose wipers are in engagement with contacts similar to bank contacts 185, 186, and 187 and multiplied with'them, or by the armature 112 of the line switch LS in an operated position to which ground may be supplied from a succeeding switch, as is well known in the art. A circuit will then be closed from ground by way of contact 186, test wiper 96, armature 44 and the Working contact, the resting Contact and armature 50, and through the Winding oit' the test relay 10 to battery. Test relay 10 energizes and prepares a lockingcircuit for itself at armature 4-1 and the working contact, opens the initial impulsing circuit at armature 42, and places a busy tone from the busy machine B on the lower talking conductor at armature 43 andthe working contact. Each time the wiper 06 passes over test contacts similar to contact 186 of busy lines, the test relay 10 momentarily operates and actuates its armatnres. The armature 45and the working coi'itact however, serve the purpose of maintaining the rotary impulsing current complete until the desired time has been reached. At the termination of the impulses tor the rotary movement, relay 11 deencrgizes and opens the impulsing circuit at armature 41-5, and by the retraction of armature let permits the completion of the holding circuit for the test relay 10 at the normally closed springs controlled by armature 1 1. The test relay 10 i now held operated over a circuit which extends from ground by way of the resting contact and armature 26, working contact and armature 28, armature 33 and the resting contact, armature l1 and the working contact, normally closed springs controlled by armature 4 1, resting contactand armature 50, through the windings of test relay 10 to battery, and can only be deenergized by the release of the connector C. The busy test relay 10 will not be operated, and at the retraction of armature 44; a circuit is completed for the switching relay 12 which may be traced from ground by way of the resting contact and armature 26, working contact and armature 28, armature 38 and the resting contact, armature 411 and the resting contact, through the upper winding of relay 12, resting contact and arn'iature 44-, test wiper 96, test contact 186, through the winding of relay 102, of the line switch LS, interrupter springs 116, and through the winding of the stepping magnet 103 to bat tery. Stepping magnet 103 is not operated over thiscircuiton account of the high resistance of "relay 102. By reason of a mechanical interlocking device between relay 102 and relay 101, relay 102 operates its armatures just sutliciently to separate them from their resting contacts without permitting them to engage their working contacts. Switching relay 12 operates and opens a point in the release circuit, to be described later, at armature 18, opens a point in the testing circuit at armature 50, transfers the impulsing circuit from rotary magnet 16 to the frequency selecting n'iagnet 18 at armature 51, and closes points in the talking circuit at armatures 17 and 52. A protecting ground is also placed on the test contact 186 from ground by way 01 armature 19 and the working contact, and wiper 96 engaged with contact 186. This prevents the line to substation A from being seized by some other connector at this tn in operating, switching relay 12 also closes a locking circuit for itself at armature 59 Therefore, the final digit to be digitO. When the calling device is operated for this digit, the line relay 3 transmits ten impulses to the stepping magnet 18 of the frequency selecting mechanism FS over a circuit which is similar to that already traced in connection with the rotary magnet 16, except that it now includes armature 51 and the working contact, armature 56 and the resting contact, and the winding of the stepping magnet 18 to battery. The multiple relay l1 is again energized in multiple with stepping magnet 18 and maintains its armature attracted throughout the frequency selecting movement. By the operation of stepping magnet 18, the wipers 90 and 91 are rotated step by step and are finally brought to rest in engagement with the tenth contact of their respective banks. On the first movement of the Wipers 90 and 91, the oil-normal springs 64 are closed, thereby preparing a circuitfor the ring control relay 13. At the termination of the impulses to the stepping magnet 18, the multiple relay 11 deenergizes and closes a circuit for ringcontrol relay 13 from ground by way of the resting contact and armature 46, closed springs 64, and through the winding of the ring control relay 13 to battery. Belay 18 operates and closes a locking circuit for itself at armature 57 and the working contact; prepares circuit for the release magnet 17 at armature 55 and the working contact; and opens the impulsing circuit at armature 56. In operating, relay 13 also connects the frequency selecting wipers 99 and 91 to the talking conductors at armatures 53 and 58 and their working contacts. The circuit for ringing current is thereby completed and may be traced from the inging current generator R and its interrupter springs, conductor 125, bank contact 88, wiper 90, working contact and armature 53, resting contact and armature 38, armature 47 and the Working contact, wiper 95, bank contact 185, normally closed switchhook contact at substation A and through the ringer at the said substation to ground. The above circuit is intermittently opened and closed by the ringing interrupter T, and the ringer at substation A is operated at intervals to signal the called subscriber. It is understood, of course, that the ringing current also flows through the ringers o1 substations A to A, inclusive, at the same time, but the ringers at these other substations-are so tuned that they will not respond to the ringcurrent of the frequency now being used. This is in accordance with the well known practice of harmonic signaling, in which only one subscriber of a party-line is signaled at one time. In operating relay 13 also closes the ring-back tone circuit at armature 54 and the working contact. This ring-back tone is reproduced in the calling subscribers receiver and signifies that the called subscriber is being signalled. It is obviously desirable to have the ring-back tone of the same pitch regardless which of the ringing generators is used to signal a called subscriber. In this case the generator connected to the conductor 122 is used for supplying the ring-back tone current, as is shown in the drawing.

l hen the called subscriber at substation [1 removes his receiver to answer the call, the ringer at substation A is disconnected and a direct current circuit is completed extending from the superimposed battery at the ringing generator R to conductor 201, as previously traced, through the substation A to conductor 202, bank contact 187, switch wiper 97, working contact and armature 52, armature l0 andresting contact, armature 5S and the working contact, Wiper 91. bank contact 80, through the lower winding of the ring cut-oil relay 9, to ground. The ring cut-oil relay 9 energizes and closes a lock ng circuit for itself at armature 39 which may be traced from groimd at armature SO and the working contact, arma turc 35 and the resting contact, the worklllfl' contact and armature 39, through the upper winding of the ring-cut-oii relay 9, to battery. In operating, relay 9 opens the ri ging circuit and its own initial. energizing circuit at armatures 38 and 40, at the resting contacts, and finally completes the talking connection at the working contacts. T he calling and called subscribers now hold conversation as they desire. The engagement or" armatures 98 and l9 with their working contacts also closes a circuit for the upper and lower winding of the back bridge relay 2. The back bridge relay 2 operates and supplies another ground to holding conductor 99 at armature 23 and the working contact, and at armaturcs 20 and. 21 reverses the battery potentials as supplied over the calling line through relay 8. The purpose of this reversal of battery over the alling line is for operating meters or to give supervision or tor other purposes as are well known in the art. The operation of armature 22 has no utility in this type of call.

hen the conversation has terminated, the two subscribers will replace their receivers on their respective switchhooks. Replacthe receiver at A opens the bridge across the conductors 202 and 201 thereby opening the circuit of the back bridge relay 2. Back bridge relay 2 deenergizes and removes the ground supplied to lockin conductor 99 at armature 23, and at arn'iatures 20 and 21, reverses the battery supplied to the calling line through the line rclav 8 back to normal. Replacing the re at the calling substation opens the e across the calling line, thereby opening the circuit of the line relay 3. Line relay 3 deenergizes and opens the circuit of the release relay 5 at armature 24. Release relay adeenergizes and removes the ground potential supplied to the release conductor 73 and 83 at armature28, and at armature 3O removes the ground potential supplied to the locking conductor 99. The holding circuits for relays 9 and 12 are thereby opened. Relays 9 and 12 deenergize and release their respective armatures. The release of switching relay 12 closes the release circuits of magnets 14 and 17 at armature 48, which may be traced from ground by way of armature 24 and the resting contact, armature 29 and the resting contact, armature 48 and the resting contact, and from this point through the winding of release magnet 17 tobattery by way of arn'iature 55 and the working contact, and through the winding oi? release magnet 14 to battery by way of the off normal springs 60 which were closed upon the first vertical movement of the switch. The release magnets 14 and 17 energize and restore the switch to its normal position. The disengagement of wiper 96 from contact 186 opens the circuit of the switching relay 102 of the line switch LS which therefore deenergizes and restores its ar-. matures back to normal.

In the above explanation it has been shown how the connector C may operate and function as a local connector in setting up a call to a substation on a partyline. The connector G is also accessible to the toll operator by means of toll selectors attheir bank contacts such as 75, 76, 77, and 78, and when seized by a toll operator will function asa toll connector in setting up a toll connection toa subscriber on a party line.

For the purpose of describing how the connector C operates and functions when employed in connection with setting up a toll call. to a subscriber on a party line, it

will be assumed that the long distance oporator at the local automatic exchange has received the information that a long dis tance connection is desired with the partyline substation A. It will again be as sumed that it requires four digits to select a line, and an. additional digit to select the frequency of ringing current when calling a substation on a partydine. The local toll operator completes the desired connection in the usual manner by inserting the calling plug of a cord into the jack of a trunk extending to an idle toll first selector, and dialling the directory number of the substation A.

In response to thefirst digit dialled, the

toll first selector raises its wipers opposite the level oi. bank contacts at which access is had to the proper group of toll transmission selectors, and then rotates them to select a trunk to an idle toll transmission selector bank contacts 75,76, 77, and 78. f

trunk selected is the trunk to connector (3,

comprising conductors 71, 72, 7'3, and 74, accesslble at the toll transmission selector Upon the seizure of the connector C by the toll transmission selector, a bridge is placed across the conductors 71 and 72, thereby completing a circuit for the line relay 3 by way of armatures 36 and 37 and their resting contacts, through the lower 'windingot series relay 4, normally closed springs controlled by armatures 20 and 21, through the lower and upper windings of line relay 3 to groundand battery, respectively. Line relay 3 energizes and closes a circuit for the release relay 5 at armature 24. Series relay 4-. energizes and prepares a point in its look ing circuit at armature 26 and the working contact, prepares an energizing circuit for the back bridge relay 2 at armature 25 and a the working contact, and prepares an initial energizing circuit for the changeover control relay 7' to-bedescribed later, at arma ture 27 and the working contact. type of call a holding ground is supplied to releaseconductor '7 3 and to the toll ringing conductor 74 by way of contacts 76 and 78 respectively from the toll transmissionselector. Release relay 5, upon energizing, closes a locking circuit for the series relay 4 at armature 28 and the working contact, and at armature 29 and the working contact prepares an inipulsing circuit for the vertical magnet 15, rotary magnet 16 and the stepping magnet 18, which operate in the sequence and manner described in connection. with the set-ting up of a call between two local subscribers. In response to the third digit dialled by the toll operator the vertical magnet 15 operates as previously described to raise the switch wipers 95, 96, and 97 step by step until they are opposite the level of bank contacts in. which the line extending to the substation A terminates. In response to the fourth digit dialled the rotary magnet 16 operates and rotates the switch wipers 95, 96 and 97 into engagement with the set of bank, contacts associated with the line to substation A these being the bankcontacts 185, 186, 187. I v I It the line to substation A is busy at'this time, busy relay 10 will operate from ground on the test contact 186, as previously de scribed, and apply the busy tone from the In this 7 fin the desired line is busy. A supervisory lamp a close a locking circuit for itself at armature 59, transfer the impulsing circuit to the stepping magnet 18 at armature 51, and connect the talking conductors at armatures 47 and. 52. Relay 102 of the line switch LS operates as described previously. In response to the fifth and last digit, which in this particular case has been assumed to be the digit 0, the stepping magnet 18 rotates the frequency selecting wipers 90 and 91 into ongagement with the bank contacts 88 and 90, respectively. On the first step of the wipers 90 and 91, off normal springs 64 are closed. At the termination of the stepping action of the stepping magnet 18, the multiple relay 11, which is energized in multiple with the stepping magnet 18, deenergizes and closes a circuit for the ring control relay 13 and the backbridge relay 2. These circuits may be traced from ground, at the resting contact and armature 46, closed springs 64, through the winding of the ring control relay 13 to battery, and also through the upper winding of the back bridge relay 2 to battery by way of armature and tle working contact. Ring control relay 13 operates and at armatures 53 and 58, connects the Wipers 90 and 91 to the back contact of armatures 38 and respectively, prepares a release circuit for the release magnet 17 at armature and the working contact, opens the impulsing circuit at armature 56, closes a holding circuit for itself at armature 57 and the working contact, and also prepares the ring-back tone circuit at armature 54 and the working contact. The back bridge relay 2 operates and prepares the initial energizing circuit for the changeover control relay 7 at armature 22 and the working contact, and, at armatures 20 and 21, reverses the battery potential supplied to conductors 72 and 71 through the relay 3. Re versing. the battery potential supplied to conductors 72 and 71 causes a reversal of current in one of the windings oi an electropolarized relay in the toll transmission selector (not shown). This electro-polarized relay operates and closes a locking circuit for itself, causes the lighting of a super sory lamp in the operators cord, and con.- nects a battery supply to conductors 72 and 71 which directly opposes the battery as now supplied through the line relay 3 of the con nector C. This causes the line relay 3 to deenergize and retract its armature 24. This opens the circuit of the release relay 5 which,

however, remains energized long enough for an impulse ot current to be sent irom ground by way oi? armature 24 and the resting cone- /vr WM: .P) 29 t 1 q .1; O. t .1. tact, mainline anc n it or 3.111, con act, springs 62 and 63, armature 32 and the rest ing contact, working contact and arn'ia-ture 27, worki l contact and arn'iature 22, thrr igh the winding of the change-over conthe working contact and armature 'i change-over relay 8 operates and con- "ra nos 30., 37 id their working contacts. bcin remembered that rmatures 38 and .nd 52, are in an operated position. .tion of thechange-over relay 8 also cLmooaiiects the line relay 3 from the conductors 71 and 72. As a further result of the decnergization of the release relay 5, the holding circuit for the series relay 4 i s opened at arn'iature 28, the release circuit prepared. at armature 29 and the resting con-tart, and the ground supplied to the locking conductor 99 by way of armature 30 is removed. Series relay 4 deenergizes and opens the circuit of the back bridge relay 2 at armature 25. Back bridge relay 2 deenergi l s and restores its armature to normal.

At this point in the operation of the con" ncctor C, the change-over relay 7 is held operated over the release conductor 73, the change-over relay 8 is in the operated position under the control of relay 7, the ring control relay 9 is held operated over the toll ringing conductor 7 4, relay 12 is held operated from ground on the locking conductor 99 supplied to this conductor by armature 35 and the working contact, and the ring control relay 13 is held operated over its own locking circuit controlled by armature 57.

The lighting of the supervisory lamp at the control operators position gives the local toll. operator the signal that connection with the subscriber A has been obtained. She may now signal the subscriber at the substation Ap at her will. To signal the subscriber at substation A the local long all distance operator momentarily actuates the holding circuit at armature 39, and complete the circuit for ringing current at armature.

3S and its resting contact. The release of the relay 9 also closes a circuit for the ring back tone at the normally closed springs controlled by armature 38. The ring-back tone is reproduced in the local toll operators receiver, signifying that the called subscriber is being signaled. Since the wipers 90 and 91 are now in engagement with the contacts 88 and 80, the ringing current circuit is the same aswas previously described in connection with the setting upof the local call, extending from the ringing. current generator It over the line conductor 201 to the ringer at the substation A, and being in termittently opened and closed by the operation oi the interrupter I.

\Vhen the called subscriber at substation A removes his receiver to answer the call, the ringer at substation A is disconnected and the direct current circuit, as previously described, is completed extendin from the superimposedbattery at the ringing gen orator t, over the talking loop including line. conductors 201 and 202 and the substation A the wiper 91, bank contact 80, through the lower winding of the ring cutoff relay 9 to ground. The ring cut-off relay 9 will again energize and close the locking circuit for its upper winding at armature 39, and completes the talking connection at armatures 38 and 40 and their working contacts. The local toll operator may new converse with the subscriber at substation A and inform the subscriber that a hu 3; distance connection with him is being extended.

If the extension of this long distance call does not include many intermediate oiliccs, or comes from a relatively short distance so that the calling party can quickly be called to his telephone, the subscriber at substation A is instructed to hold his receiver and wait for the calling party to begin the conversation. It may be assumed, however, that it may take some time before the distant calling subscriber can be summoned to the phone, in which case the subscriber at sub station A may replace his receiver, but he is requested to be in readiness to immediately answer the call when he is again signaled.

The local toll operator now notifies the distant toll operator that connection has been completed with the local called subscriber. The local toll operator waits until she is notified thatthe distant calling subscriber has been summoned to the phone, and when she is notified, the local toll operator will again signal the subscriber at substation A?" by momentarily operating the signaling key in. her cord circuit. The ring-cut-ofi relay 9 will again deenergize as described before and cause the ringing current to be supplied to the line conduci'ior 201. When the subscriber at substation A has re moved his receiver, the energizing circuit for the ring cut-off relay 9 is again closed and relay 9 operatesto complete the talking connection. 'The subscriber at the distant calling); substation may now. converse with the subscriber at substation A ileenirving the receiver at substation A also placesa bridge across the conductors 201 and 202, which closes a circuit for the battery teed relay in the toll transmission selector (not shown). This battery feed relay supplies talking battery .to the called. subscrier a: d also operates to extinguish the supervisory lamp in a toll operators cord circuit, thus giving the toll operator the usual supervision. I

l hen the conversion has terminated, the two subscribers will rcplace'their receivers on their respective switchhooks. Repiao the receiver at substation A opens the bridge across the conductors 201 and 202, thereby opening the circuit for the previously mentioned battery teed relay in the toll transmission selector. This battery reed relay deene-rgizes and again closes a' circuit for the supervisory lamp in the toll operacrMs cord. circuit. The lighting of this supervisory lamp signals the'loca toll op erator that the called subscriber has replaced his receiver, The local toll operator will also receive the usual disconnectsignal ifrom the origg'inating distant toll operator. Upon rr eiving these signals, the local toll "ll proceed to pull down the cony reniovin the calling and answering plugs from. their respective jacks. Rerthc calling plug from the jack will the selectors and the toll transmisil ctor in the usual manner. \Vhen the toll 'ssion selector is released, ground isremoved from the release conductor 73 and from the ringing conductor 74. The removaloi. ground from conductor 74 opens the holdi'i'ig'circuit for the ring control relay 9; the removal of ground from the release conductor 73 opens the holding circuit tor the changeover-control relay 7. Relays 7 and 9 are deenergized and fall back to normal. In deenergizing, relay 7 also opens the circuit for the change-over relay 8 at a mature 34. and removes ground from the holding conductor 99 at armature 35, there-- by opening the circuit for switchingrelay l2. Relays 8 and 12 deenergize and restore their armatures to normal. In deenergizing, relay l2 closes the release circuit for release lie and also the i'reruenc 1 selectiim wi JGIS 90 and 91 back to their normal position. At the restoration of the wipers 90 and 91, off normal springs 6 1 are separated. The holding ircui; tor the ring control relay 13 is thereby opened and t is relay deene-rgizes restoring its a matures back to normal. The circuit of t 1e release magnet 17 is opened at armature i Vhen the switch shaft returns to normal oil normal springs 60 are separated and springs 68 and 62 are separated and springs (31 and 62 are closed. The connector C is now in its normal condition, ready to re ive another call.

A brief explanation will now be given of the manner in which the other substations of the line may be signalled either by a local subscriber or by the toll operator. Each of the substations A, A A, and A may be signalled independently by dialling the digits 6, 7, 8, and 9, respectively, as the final digit, and the operations are exactly the same as when substation A is called, except that a difierent frequency of ringing current is selected. it is understood in this connection that the conductors 121-424, inclusive, all ext-end to separate ringing current generators similar to generator B and that these generators are all of different frequencies. The ringers at the five substations just retel-red to are all connected from the line conductor 201 to ground. In order to operate the ringers at the remaining substations A to 11", inclusive, which are connected from the line conductor 202 to ground, digits 1, 2, 3, el-and 5, respectively, must be dialled the final digits. Suppose for example that is desired to call the substation A. The ringer at this substation is tuned to the same frequency as the ringer at substation A. The final digit to be called in this case is the digit 5, in response to which the wipers of the frequency selecting mechanism F3 are advanced five steps into engagement with the fifth contacts in their respective banks. When the wiper 91 comes to rest on the fifth contact, contact 89, the ring-generator R shown on the drawing is again selected, as the first five contacts in the bank associated with the wiper 91 are connected in multiple with the last five contacts in the bank associated with the wiper 90. \Vhen the ground is removed from the conductor 74 as a result of the actuation of the ringing key by the local toll operator, the ring cut-oil relay 9 is dcenergized, thereby completing the ringing circuit substantially the same as previously described except that in the present case, the ringing current is applied to line conductor 202 by way 01 conductor 125, bank contact 89, and wiper 91, instead of to conductor 201 by way of bank contacts 88 and switch wiper 90. The ringing current is then supplied over conductor 202 to the ringers of the substations A to A inclusive, to ground. The ringer at substation A is accordingly operated. inclusive, may be called in the same manner by dialling, as the final digit, the digits which correspond to these substations.

Having described this invention, what is considered new and is desired to have pro tected by Letters Patent will be pointed out in the appended claims.

hat is claimed is:

1. In a telephone system, a plurality of sources of signalling current, a connector switch provided with movable terminals 00- operating with the fixed terminals of called lines, a selecting switch individual to said first switch provided with movable terminals cooperating with the fixed terminals of said signalling current sources, separate pairs of toll and local talking conductors terminating in different parts of said connector switch, means for placing both said switches under the control oi? said pairs separately, and means whereby the connector is adapted for toll operation when controlled over said toll conductors.

2. In a telephone system, a connector switch, party lines, a plurality of signalling sources, a first and second trunk line terminating in different parts of said switch, means for operating said switch to select and connect with any one of said party lines and then to select any one of said signalling sources, and means for placing first said means under the control of either trunk line separately.

3. In a telephone system, a connector switch, party lines, a plurality of signalling sources, a first and second trunk line terminating in said switch, said trunk lines being of diti'erent character, means for operating said switch to select and connect with any one of said party lines and to select any one of said signalling sources, means for placing first said means under the control of either trunk line separately, and means whereby diilerent talking circuitsare set up depend.- ing upon over which trunk the connector is seized.

l. In a switching device for extending connections to party lines operable in accordance with the last three digits in a telephone number, means for selecting the line responding to the first two digits received, a plurality of signalling current sources, means for operating said switch in accordance with the third digit to select a signallin current source, two trunk lines terminating in said device, means for placing said device under the control of said trunk lines separately, and connections whereby said switch operates differently depending,

Substations A to A upon which trunk is controlling the switch.

5. In a telephone system, a connector switch, means for seizing the switch over either of two paths, aplurality of sources oil signalling current and a plurality of lines accessible to said switch, means for directi'vely operating said switch over either path to first select a line, then select a source of signalling current, and thereafter connect the two, a relay arranged when operated to disestablish the signalling connection, connections to operate said relay when the called party answers, and additional connections controlled over one only of said paths for operating said relay.

6. In a telephone system, a combination toll and local connector, a toll trunk and a local trunk tern'iinating in said connector, a party line accessible to said connector, means for dircctively operating said connector to extend a call to said party line and selectively signal a party on said party line, and means el'l'ective before said party is signalled for adapting said connector for toll operation providing the connector is being operated over said toll trunk.

7. In a telephone system, a combination toll and local connector switch for completing connections to party lines, a signal selecting switch for signalling a party on a party line,a back-bridge relay and an impulsing relay in said first switch, means operable after said second switch is operated for momentarily operating said back bridge relay to deenergize said impulsing relay, and means responsive to the momentary energization of said baCkbridge relay and the deenergization of said impulsing relay for adapting said first switch for operation as a toll connector.

8. In a telephone system, a combination toll and local connector switch, a toll trunk line and a local trunk line terminating in said switch, means for directively operating said switch over either of said trunk lines for extending calls to a party line and for selecting a party on said party line, a backbridge relay and an impulsing relay in said switch, means operable after said party is selected providing said switch has been taken for use over said toll trunk line for momentarily operating said back-bridge re {means for directively operating said conhector to exti da call to said party line and selectively signal a party on said party line,

a relayin said connector for adapting said connector for toll operation, and means for nector to extend a call to said party line, a

ringing current selecting device, means for operating said. device to select a party on paid party line, a relay for adapting said connector to operate as a toll connector, and means eflective when said device is in an off-normal position providing the call is extended over said toll trunk for operating said relay.

11. In a telephone system, a combination toll and local connector, a toll trunk and a local trunk terminating in said connector, means including an impulsing relay operable over either of said trunk lines, for operating said connector to establish a connection to a party line, a ringing current selecting device, means for operating said device for signalling a party on a party line, a backbridge relay, a third relay operated when a connection. is being established over said toll trunk for preparing a circuit for said back-bridge relay, means including contacts controlled by said device for closing said circuit to operate said back-bridge relay,

means responsive to the operationof said back-bridge relay for appl' yingopposirig potential to said impulsing relay to release said impulsing relay, and means responsive to the operation of said back bridge relay and the release of said impulsing relay for energizing a change over relay to adapt said connector for toll operation.

12. In a telephone system, a combination toll and local connector, a toll trunk and a local trunk terminating in said connector, means including an impulsing relay operable over either of said trunk lines, for operating said connector to establish a connection to a party line, a ringing current selecting device, means for operating said device for signalling a party on a party line, a backbridge relay, a third relay operated when a connection is being established over said toll trunk for preparing a circuit for said backbridge relay, means including contacts controlled by said device for closing said circuit to operate said back-bridge relay, means responsive to the operation of said back bridge relay for applying opposing potential I to said impulsing relay to release said impulsing relay, and means responsive to the operation of said back bridge relay and the of said line relay to re said to): tell operation;

13. In a telephone system, a connector switch, a plurality of lines accessible thereto, a plurality of sources of signalling current, means for operating said connector over either of two paths to connect any of said sources of signalling current with any of said lines, said means including a bridge across the talking conductors of the switch, and means operated only when said switch is controlled over one of said paths for opening said bridge.

14:. I11 a telephone system, a connector switch including an impulsing relay and a battery feed relay, a plurality of lines, a local trunk, a toll trunk, means for directively operating said connector over either trunk to select a line and selectively signal a party on the line, means for establishing a talking circuit through said connector, said circuit including said impulsing relay and said battery feed relay in bridge thereof it the connector was operated over, one trunk, said bridge being excluded if the connector was operated over the other trunk.

15. In combination, a connector, a plurality of lines accessible thereto, a plurality of sources of signalling current, a local trunk, a toll trunk, means for directively operating the connector over either trunk to select a desired line and a desired signalling source, a bridge across thetalking conductors of the connector, means for establishing a talking circuit through said connector said circiut .including said bridge if said connector was operated over a local trunk, and means operated responsive to the selectlon of the slgnalling current source when the connector is .operated over the toll trunk to Open said bridge.

16. In a telephone system, a local trunk, a toll trunk, a connector switch accessible by way of said trunks, a plurality of lines accessible to said connector, a relay in said connector arranged to be operated when the connector is seized over either trunk, means for directively operating said connector over either trunk through contacts on said relay to select a line and selectively signal a party on said line, means in the toll trunk effective when the toll trunk has completed the'directive control of said switch to cause the release of said relay, a toll switching relay, and connections whereby said last mention relay is operated responsive to said release of said first mentioned relay.

17. In a telephone system, a local trunk, a toll trunk, a connector switch accessible by way of said trunks, a plurality of lines accessible to said connector, a relay in said connector arranged to be operated when the connector is seized over either trunk, means for directively operating said connector over either trunk through contacts on said relay to select a line and selectively signal a part on said line, means in the toll trunk effective when the toll trunk has completed the directive control of said switch to cause the release of said relay, a ring cut-oti relay, and connections whereby said last mentioned relay is placed under the control of the toll operator responsive to said release of said first mentioned relay.

18. In a telephone system, a local and a toll trunk, a connector accessible by way of said trunks, means for directively operating said connector over either of said trunks, a relay, means for momentarily establishing an operating circuit for said relay upon the termination of the directive operation of said connector only if the connector is operated over the toll trunk, said circuit being directly controlled by oil normal contacts on said connector, and means effective upon the momentary operation of said relay to adapt said connector for toll operation.

19. In a telephone system, a line, a connector switch, means for seizing said switch over either one of two paths, means for directively operating said switch to seize the line, and means for operating said switch over either path to apply ringing current of any one of a number of characteristics to said line, said last means operating in one of two ways depending upon which of the paths the switch was seized over.

20. In a telephone system, a line, means for seizing said line over either one of two paths, means arranged when operated to apply signalling current to the line, a directively operated device for predetermining the characteristics of said signalling current prior to the operation of said means, and means for automatically operating said means responsive to the selection of the kind of current to be applied if the line is seized over one path, and under the control of the seizing party it the line is seized over the other path.

21. In a telephone system, a connector, local and tell trunks, means for seizing the connector over a local or over a toll trunk, a plurality of lines, means for directively operating the seized connector to select any desired one of said plurality of lines and for applying thereto signalling current of any desired one of a plurality of characteristics, and means in the connector operable by the toll operator for preventing the application of signalling current to the line selected.

22. A switching device for extending connections to party lines operable in accordance with the last three digits in a telephone number, a local trunk line and a toll trunk line terminating in said device, means in said device controlled over either trunk line for selecting a line responsive to the first two digits received, and means in said device controlled over either trunk line for selecting a particular party on the line responsive to the last digit received.

23. In a telephone system, a connector, two trunk lines terminating in said connector, a party line, a relay in said connector controlled over either trunk line for directively operating the connector to extend a connection to said party line, a signal current selecting, device associated with said connector, and means effective only when the called line is idle for placing said selecting device under the control of said relay.

In Witness whereof, I hereunto subscribe my name this 17th day of June, A. D. 1925.

ARTHUR J. RAY. 

